The structure of insect ferritins and the regulation of their expression is of particular interest for two main reasons. Firstly, insects can be useful biological models for studying complex processes, such as dietary iron absorption without involving vertebrate animals. Secondly, the understanding of insect iron metabolism could suggest new strategies for control of hematophagous insects that act as vectors of disease. With these goals in mind we have proposed to study the iron metabolism in Manduca sexta. Drosophila melanogaster with its sophisticated genetics provides an extremely powerful system for mutational analysis of the structure-function relationships. Based on this we propose to expand the study of insect ferritins using D.melanogaster. We propose to: 1) characterize ferritin and develop molecular probes for ferritin from D.melanogaster; 20 localize ferritin genes on polytene chromosome maps and determine the pattern of regulation of ferritin expression during development and under conditions of different iron abundance' and 3) obtain ferritin mutants and use them to study the structure and function of ferritin in D. melanogaster. To achieve these goals we propose to: purify ferritin from D.melanogaster larvae and characterize it; produce antibodies against it, determine N- terminal sequence of ferritin subunits(s0 and clone cDNAs for them; localize ferritin gene(s) by in situ hybridization on polytene chromosomes; study the developmental and iron-regulated expression of ferritin by western and northern blotting; produce and analyze ferritin null mutants and rescue them by P-element mediated transformation.